162 BACTERIOLOGICAL CHEMISTRY LESSON 



B. ACTION OF CHLOROFORM ON FERMENTS AND 

 ENZYMES. 



(1) Suspend a little yeast in lukewarm sterile water. 



(2) Pour a little of this suspension into two large test- 

 tubes. 



(3) Shake up the contents of one of these tubes with an 

 equal volume of chloroform for five to six minutes, but 

 leave the other for control purposes (vide infra). 



(4) Allow the chloroform to settle to the bottom of the 

 tube. 



(5) Add a little of the supernatant liquid to two test- 

 tubes, containing a dilute solution of cane sugar. 



(6) Keep these tubes at 38 -5 C. 



Test one tube with Fehling's solution after four to 

 six hours : marked reduction of copper. 



Test the other tube with Fehling's solution after 

 twenty-four hours : marked reduction of copper. 



(7) The other tube, containing a little of the yeast 

 suspension, must not be shaken up with chloroform. 



(8) Add a little of the original suspension to two tubes, 

 containing a dilute solution of cane sugar, 



(9) Keep these tubes at 38 -5 C. 



Test one tube with Fehling's solution after four to 

 six hours : marked reduction of copper. 



Test the other tube with Fehling's solution after 

 twenty -four hours : no copper reduction. 



